1. Field of the Invention
The present invention relates to a plant guard which is intended to protect a plant against attack by pests and which comprises a knitted hose-shaped net which is intended to form a casing around the plant; hang threads attached to one end of the net and forming the bottom thereof; and a net-closure thread provided at the other end of the net for gathering together the upper part of the guard. The invention also relates to a method and a machine for producing such plant guards.
2. Description of the Prior Art
It is a generally recognized problem that newly planted plants are often attacked by different types of pest, particularly insects. For example, the forestry industry suffers large economic losses each year as a result of attack by pine weevil and other pathogenic insects for example. Since the use of chemical sprays is often ineffective in controlling such pests, and indeed often unsuitable with respect to the health hazards involved and to the environmental harm caused, various mechanical guards have been developed. One such guard is described in European Patent Application No. 84850020.3, published under Ser. No. 0114798. The guard comprises a net structure which is intended to enclose a newly planted plant, either totally or partially, and which decomposes when the plant has grown and become more durable, and ultimately disappears completely. The guards are applied to respective plants manually, by inserting the plants into a tube onto which a number of guards have been mounted. When a plant is drawn out of the tube, the plant engages bottom threads located on the lowermost guard and extending transversely of the outlet orifice of the tube, therewith to entrain the guard with the plant. The upper part of the guard is then gathered around the plant with the aid of a tie, which is tied manually around the plant, whereafter the plant is ready for planting.
Such plant guards have been found highly effective against attack from pine weevil and other pathogenic insects, but because the task of manually gathering and tying the guard is relatively time-consuming, the use of such guards on a large scale is often found too costly to be viable.